Cardiac information is normally obtained using conventional devices and techniques, such as manually operating a stethoscope and listening to the patient's heart, or attaching electrodes to the patient and obtaining an electrocardiogram (ECG) which provides information about the patient's heart.
Ultrasound systems currently are utilized to obtain information about a patient's heart. However, ultrasound systems currently do not extract the patient's heart rate from the acoustic ultrasound information because it is believed that other techniques, such as ECG techniques, are better suited for this purpose. Therefore, although ultrasound systems exist that display the patient's heart rate, the heart rate is obtained using ECG techniques, which require the attachment of leads to the patient's body. Ultrasound systems comprise a probe that transmits high frequency acoustic waves into a patient's body and receives acoustic waves back scattered by objects within the patient's body. The back scattered acoustic waves, or echoes, are converted into electrical signals and the electrical signals are converted into pixels, which are displayed on a display monitor of the ultrasound system. The image displayed on the display monitor represents an anatomical image of the scanned area in the patient's body.
In many cases, it is useful to provide the technician or physician operating an ultrasound system with the patient's heart rate. This information may be useful in analyzing the image being displayed for diagnostic purposes. It would also be desirable to be able to extract cardiac rate information from the back scattered acoustic waves. This would eliminate the need to use ECG techniques or a stethoscope to obtain the cardiac information.
Accordingly, a need exists for a method and apparatus for extracting cardiac information from acoustic information acquired using an ultrasound system.